Embodiments of this disclosure relate generally to a device for determining an azimuth reference line, and more particularly, to an azimuth determination system that has improved accuracy over current gyrocompasses, and which provides an azimuth determination every few hours that is independent of the need for a pier with long term stability to hold a reference mirror.
The testing of high accuracy inertial instruments and systems, such as those used on Intercontinental. Ballistic Missile Systems or Submarine Launched Ballistic Missile Submarine Systems, generally require that an accurate azimuth reference line be available. These instruments and systems may be tested in laboratories that have access to a precision azimuth reference in the form of a mirror on a stable concrete block. The azimuth of the mirror normal is generally referenced to north using periodic “star shots” of the North Star, Polaris. Star shots are lengthy procedures that may be performed as many as 4 times per month, to as few as 4 to 8 times per year.
To provide a stable mirror reference between star shots, the mirror is mounted on massive concrete piers and often anchored to the ground through multiple pilings that may extend up to a hundred feet below the ground level. Once built it may take several years for the structure to cure and settle, only then will it be clear if the design is a success.
The option of replicating the stable-pier infrastructure in different locations is expensive. Furthermore, replicating the stable-pier infrastructure may be extremely risky based on soil conditions where the stable-pier infrastructure will be located. Furthermore, geology or geography-introduced errors may not be controlled in certain areas.
Less complicated systems using a gyrocompass have been designed to calculate an azimuth reference line. However, these types of systems generally do not have the desired accuracy of the stable-pier infrastructure system.
Therefore, it would be desirable to provide a system and method that overcomes the above problems. The system and method will improve accuracy over current gyrocompasses which have many error sources and provide an azimuth determination every few hours that is independent of the need for a long term stable pier to hold a reference mirror.